This invention relates to fretted stringed musical instruments.
Fretted stringed musical instruments have been known for centuries and are popular musical instruments which have been used by musicians of various cultures to express their music. A fretted musical instrument employs one or more elements termed frets which function to shorten the length of a vibrating string by stopping the string at a precise point to thereby alter the pitch or frequency of the sound produced by the vibrating string. Fretted musical instruments may be generally divided into two catagories: those having fixed frets and those having moveable frets. Examples of musical instruments with fixed frets are guitars, banjos, ukeleles, dulcimers, and the like, each of which is provided with relatively narrow ridged fret members of a hard surface finish extending transversely of the fingerboard at precisely spaced locations along the length of the overlying strings. The frets are typically embedded in transverse mating slots in the fingerboard in such a fashion as to be difficult to remove, and the fingerboard adhered to the facing surface of the neck by glue and/or wood screws so that a permanent bond is created between the fingerboard and the neck. Thus, while individual worn frets can be replaced by new frets, the fingerboard cannot. Examples of stringed musical instruments employing moveable frets are the lute and other instruments popular during the Renaissance and Baroque periods in Western Europe, the sitar of India and other instruments which employ mechanisms for enabling the location of a fret relative to the length of the overlying strings to be changed.
In a fixed fretted stringed musical instrument, the available tones are fixed and finite and are predetermined by the distance between the individual frets and the remaining vibration stopping point for the strings, such as the bridge of a monochord or koto, or the saddle of a modern guitar. The number of available tones on stringed musical instruments provided with moveable frets is theoretically infinite. However, in practice the number of tones actually employed is limited by the subjective aesthetic judgment of the musician.
The set of available tones provided by a fretted stringed musical instrument may be referred to as a tonal scale. In fixed fretted stringed musical instruments, the tonal scale is invariant and determined in advance by the manufacturer of the musical instrument. For example, in modern guitars, banjos, ukeleles and the like, the commonly available scale is the equal tempered scale. This tonal scale was invented and introduced into Europe in about the year 1700 A.D. and has been widely implemented in musical instruments in Western civilization primarily since this arrangement permits modulation between any of the 12 major and 12 minor keys comprising the tonal scale. In movable fretted stringed musical instruments, various tonal scales can be provided by adjusting the individual placement of each of the frets in accordance with the musician's subjective desires. However, readjustment of known movable fretted stringed instruments is time consuming and subject to the vagaries of the subjective asthetic capabilities of the person adjusting the device.
Both professional and amateur musicians using fixed fretted stringed musical instruments suffer from what may be termed "scale limitation", viz. the fact that the only fixed fretted stringed instruments commonly available on the market employ the equal tempered scale alone. Because of this "scale limitation", countless melodies from other cultures and other eras cannot be performed on commonly available fixed fretted stringed musical instruments. Thus, in order to perform musical compositions written for other tonal scales than the equal tempered scale, the musician must either purchase an extremely costly, custom made fretted stringed instrument, or attempt to employ one of the known types of moveable fretted stringed instruments. The former alternative is also inconvenient since the number of different instruments required is equal to the number of different tonal scales. While some known movable fretted stringed instruments can be adjusted to provide a different tonal scale in which the music of a past or present culture has been written, the adjustment process is long, difficult, imprecise and impossible to perform unless the musician is already familiar with the desired scale and is possessed of perfect pitch or is extremely well trained in tuning. Even under these optimum circumstances, however, a performer desiring to adjust a movable fretted stringed instrument of known type to a different tonal scale must stop his performance for the length of time required for the adjustment, which is at best inconvenient to both performer and audience and at worst physically impossible given the time limitation on a conventional concert performance. As a result, most performers are discouraged from exploring the numerous musical possibilities available with different tonal scales.